Update documentation to include a link to the GitHub repo and installation instructions (#147)

Author: werdnum

doc/index.rst

@@ -6,10 +6,15 @@
 python-json-patch
 =================
 
-*python-json-patch* is a Python library for applying JSON patches (`RFC 6902
+`python-json-patch <https://github.com/stefankoegl/python-json-patch>`_
+is a Python library for applying JSON patches (`RFC 6902
 <http://tools.ietf.org/html/rfc6902>`_). Python 2.7 and 3.4+ are
 supported. Tests are run on both CPython and PyPy.
 
+**Installation**
+.. code-block:: bash
+  $ pip install jsonpatch
+..
 
 **Contents**